The study, “Diabetes mellitus in Friedreich Ataxia: A case series of 19 patients from the German-Austrian diabetes mellitus registry,” was published in the journal Diabetes Research and Clinical Practice.
FA is a multisystem genetic disease with a progressive clinical course that involves the neuromuscular and endocrine (hormonal) systems.
Diabetes mellitus, also known simply as diabetes, refers to a group of metabolic disorders in which there are high blood sugar levels over a prolonged period. There are two types of diabetes — Type 1, in which the body doesn’t produce insulin — the molecule that helps metabolize glucose, and Type 2, where the body is resistant to the insulin that is present.
According to the study, it is estimated that 8-32% of FA patients have diabetes. The large variance in these numbers is attributed to the use of different diagnostic tests and changes in diagnostic criteria over time.
A previous study reported that 49% of 41 FA patients who were not previously diagnosed with diabetes had impaired fasting glucose (sugar) levels and/or impaired glucose tolerance.
Researchers have hypothesized that diabetes is prevalent in FA patients due to a dysfunction in pancreatic beta cells, which produce insulin, beta cell loss, insulin resistance, or increased body fat mass — all of which are frequently seen in FA patients.
To best treat patients, it is important to understand the peculiarities of diabetes in FA patients. However, not much is known since there are very few patients with both diabetes and FA, which is itself a rare disease.
Therefore, researchers set out to assess the characteristics of diabetes in FA patients using the German-Austrian diabetes registry, consisting of 200,301 patients, of whom 19 also had FA.
Upon assessment of these 19 patients, researchers found that the phenotype of diabetes in FA patients was intermediate between Type 1 and Type 2.
Ketoacidosis, a life-threatening diabetic complication where the body produces high levels of acids called ketones, was frequently observed.
The blood glucose levels of patients with both FA and diabetes (average of 356 mg/dl) were similar to those seen in Type 1 diabetes (average 384 mg/dl), but higher than Type 2 (average of 233 mg/dl).
FA patients’ mean age at diabetes onset was higher (about 29 years old) than patients with Type 1 diabetes (about 23 years old) but lower than Type 2 patients (about 49 years old).
Type 1 diabetes is characterized by autoimmune processes in which anti-beta cell autoantibodies destroy the insulin-producing beta cells in the pancreas. Therefore, the researchers also looked into levels of these autoantibodies.
Interestingly, they found that the rate of anti-beta cell autoantibodies among FA patients with diabetes was 42.9%, which was higher than Type 2 patients (13.5%) but lower than Type 1 patients (81.9%).
Regarding therapy, 63.2% of FA patients received insulin therapy, 21% were on insulin plus oral antidiabetics, and 15.8% made lifestyle changes.
The hemoglobin A1c (HbA1c) test tells the average level of blood sugar over the past two to three months. HbA1c levels in FA patients with diabetes were lower than in Type 1 and Type 2 diabetes patients — suggesting that FA patients had good overall diabetes control.
Results from this analysis indicate that diabetes in FA patients can be well-controlled by an individualized treatment regimen with insulin or oral antidiabetic medications.
In addition, “patients with DM [diabetes mellitus] in [FA] may show a relevant risk to ketoacidotic complications, which should be avoided,” according to the authors.